M
MeteorWayne
Guest
The GEMINIDS<br /><br />The best meteor shower of the year reaches it's peak Thursday morning Dec 14. (Night of the 13/14)<br />Since the years of the Leonid meteor storms have passed, and the Perseids have continued to diminish since the late 90's, this is now the richest and most reliable meteor shower of the year.<br />The ZHR (Zenithal Hourly Rate) of 120 per hour is matched only by the Quadrantids in January (more on that in a few weeks), a much more difficult target.<br /><br />The radiant (where the meteors appear to come from) is near Castor, one of the bright twin stars in Gemini (hence the name of the shower.) <br /><br />It rises shortly after sunset, and reaches it's highest elevation after 2AM. So, unlike so many other showers, while rates are lower in the evening, at least you can see some.<br /><br />These meteors impact the atmosphere at only 35 km/sec (22 miles/sec) unlike other well known showers such as the Perseids, Orionids, and Leonids (59, 66, and 71 km/sec respectively). That's because, unlike these other showers, they are in prograde orbits, travelling around the sun in the same direction as the earth. So, they're catching up to us from behind, rather than smacking us head on. <br />In addition, they are denser than most other meteoroids. See Geminid Gems for an explanation. So it's a different show than any of the others.<br /><br />IF the Geminids perform as expected, here are some hourly rates you might expect:<br />These are calculated using historical ZHR's, using very dark skies (dimmest stars visible Mag 6), and considering that the moon will wash out fainter meteors after midnight on the first two nights. This is for the US. If anyone would like information for other places, give me your location and I'll explain the differences. Nite refers to before midnight, AM after midnight. <br /><br />Mon Nite/ Tue AM ... 12 - /> 12/Hr<br />Tue Nite/ Wed AM ... 20 - /> 25/Hr<br />Wed Nite/Thu AM ... 30 - /> 60+/Hr (Peak at 5:45 AM EST) {1045 UT}<br />Thur <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>